In parallel with the ?Jennerian? and modified ?Jennerian? approach to vaccination against rotavirus diarrhea in which an oral live attenuated rotavirus vaccine is generated, we are pursuing other exploratory approaches to vaccination. A complete rotavirus particle consists of three capsid layers: an outer layer consisting of VP4 and VP7, an intermediate layer consisting of VP6 and an inner core consisting primarily of VP2. In this project, taking advantage of (i) the availability in our laboratory of various baculovirus recombinants expressing rotavirus proteins including VP2, VP4, VP6 and VP7 and (ii) properties of selected rotavirus structural proteins to self-assemble spontaneously and form virus-like particles (VLPs) upon co-expression in insect cells, we are pursuing the construction of recombinant rotavirus VLP subunit vaccines that can be delivered via various routes including intranasally. In addition, we are pursuing the construction of recombinant rotavirus subunit vaccines produced from prokaryotic eucaryotic expression vectors. Such purified protein subunit vaccines conjugated with selected bacterial polysaccharides can be delivered parenterally. This year, we constructed a baculovirus system expressing the VP8* subunit of VP4 of human rotavirus P serotype 1 strain Wa.